Fuel Starvation

Emmajoe · August 21, 2005, 01:39:49 PM

So, I've seen a few posts about fuel starvation. There's been discussion, but I've seen no real conclusions. It seems a pretty common problem with the mid 90s GSs.
I've got a 93 thats in good shape. it used to die on me if I'd ride for over 20 minutes at 50 plus. I've gotten it to stop dying out on me by keeping it in PRI, but it still acts like it's going to starve then gets better for a little ways and goes right back to sputtering. Who's got the answer, or should I just give up?

rclz · August 21, 2005, 01:42:35 PM

I'm no carb expert but kinda sounds like dirty carbs / float problems.

Emmajoe · August 22, 2005, 05:05:48 AM

wish it was that simple, there clean and in good working order.

scottpA_GS · August 22, 2005, 07:12:50 AM

I was having the same prob.. couldnt ride over 50 for more than 5 mins... I replaced all the fuel lines w/ new clear "fatter" line, and I got another "used" but better, petcock.. now it is running great!!! on res, on, or prime

Cant say for sure that it will solve your prob, but it did mine

I would deff start by removing the petcock, and checking it out.. make sure that diaprham looks good, then replace the lines.. its one of the cheapest things you can do anyway... :mrgreen:

davipu · August 22, 2005, 09:00:32 AM

I converted over to a non vaccum system, and removed about 3 feet of fuel hose from the system.

Emmajoe · August 22, 2005, 03:51:40 PM

So where did you find the petcock? And which years are simalar enough to a 93 to work well.

also, for davipu,
how did you convert to a non vacume system?

davipu · August 22, 2005, 04:35:12 PM

by running the two lines off the tank to a T. on the res line I put a valve so i can open it when i run low.

Jazzzzz · August 22, 2005, 05:50:53 PM

Quote from: Emmajoe
also, for davipu,
how did you convert to a non vacume system?

Like davipu said, run the lines from the tank to a T that runs straight to the carbs (maybe put in a fuel filter between the T and the carbs). The guy I bought my carbs from when I got the bike had put a pingel petcock on his tank and did not put in the extra valve for a reserve like davipu did.

Emmajoe · August 22, 2005, 06:42:45 PM

I appriciate all the advise. I'll play around with it tomarow and let you know what I find.

Trwhouse · August 25, 2005, 07:05:07 AM

Hi there,
My 1992 GS500E had the same problem a few years ago and after much trial and error, the only thing that fixed it was buying a new replacement Suzuki petcock (the frame mounted petcock on the left side that has the lever for ON, PRIME and RESERVE). Apparently the rubber diaphragm inside the petcock degrades over time and causes the problem, which doesn't allow the vacuum petcock to flow fuel as it should.
I bought my petcock from a mail-order dealer in Pittsburgh, PA, for about $50, which was $25 or so less than the local dealer.
I'd go with a new one like I did and not try for a used part, which at some point will likely have the same problem as yours does now.
I also recommend replacing your old fuel lines at the same time to get rid of one more variable and potential trouble spot. Get 1/4" black rubber FUEL line at a local auto parts place. Be sure it is marked for FUEL and NOT for VACUUM. Fuel line is made of special materials with nylon webbing to add strength. The fuel hoses do deteriorate over the years and they are cheap and easy to fix, as well as an important safety issue. Use small hose clamps and all connections on the new hoses and you will be in good shape.
There is also a second petcock on the GS500 as you probably know, but that one is a simple fuel shut-off under the tank. There is no vacuum mechanism on that petcock, just on and off.
Good luck and I hope you get it sorted out.
Yours,
Todd

sprint_9 · August 25, 2005, 01:39:41 PM

Isnt fuel starvation at wide open throttle, unless you have some other problem like crappy lines or something.

Trwhouse · August 28, 2005, 01:50:18 PM

Hi Sprint,
No, fuel starvation can happen at any throttle opening. On my bike, I would be cruising along at a steady 65-70 mph and all of a sudden, the engine just began sputtering. If I pulled in the clutch, the engine immediately cut out. and I had to coast quickly to the side of the road -- not a safe situation on the Jersey Turnpike. The term fuel starvation means that the engine is simply not getting enough fuel, no matter what the throttle setting is at.
There are plenty of other posts from people here on this well-known GS500 vacuum petcock weakness.
I hope this helps.
Yours,
Todd

bikingreenie · August 28, 2005, 03:10:32 PM

I just bought a GS500 and have been having some fuel issues. First, I had the gas tank draining into the crankcase. I cleaned petcock and carbs, and it still did it. Then I ran a single fuel line from the reserve to the carb with a shut off valve in it.

It starts and runs great for the first few minutes, then acts like it is starving for fuel and dies.
Then I unplugged the vacuum line from the left carb (left it open) and it started running good again for a minute, then did the same thing.

Any suggestions?

jordanearl · August 28, 2005, 06:20:42 PM

mine is having the same problems. I had the carbs went thru by a local shop, an it still does it. I have found that when it dies out that i can drain gas from the carbs, and it will start right back up. Im at a loss as of what to do next. I can ride around town all day, but if i hit above 60 it does it to me.

Emmajoe · August 31, 2005, 08:12:55 PM

So, I got a new petcock, didn't replace the lines yet. It still has the same problem. I can't go anywhere in the on possition, goe's ok in RES for about 30min, but it'll go all day in PRI. I'm going to replace the fuel lines over the weekend. I'll be keeping my fingers crossed

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Fuel Starvation

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